title: Clinical utility and assessment of cyclodeviation.
abstract: OBJECTIVE
  This article reviews and updates basic concepts, diagnosis and treatment of cyclotorsion.
  
  
  RESULTS
  Cyclodeviation in congenital superior oblique palsy (SOP) seems to correlate with the extent of superior oblique muscle hypoplasia. Genetic polymorphisms such as PHOX2B polymorphism, considered to be risk factors for congenital fibrosis of the extraocular muscles, may play a role in SOP and consequently in cyclotorsion. Two components of the ocular tilt reaction, ocular torsion and tilt of subjective visual vertical, seem to share similar sites of impairment in the brainstem. Harada-Ito surgery continues to be the procedure of choice in patients with isolated cyclodeviation, evidencing better outcome if less than 10° of preoperative excyclotorsion and preoperative fusion exist. Ocular torsion is not infrequent in patients with intermittent exotropia, especially in the most exo-deviated eye, emphasizing a possible role in pathogenesis. A new device for the assessment of dynamic torsion during ocular counter roll response using after-image has been described. Similarly, a new method to measure objective ocular torsion using retinal arcade tilt as a reference has been proposed. Finally, torsional data transformation such as the sum of angles of excyclodeviation, rather than using the angle of excyclodeviation of the paretic eye, is becoming increasingly popular among studies on torsion.
  
  
  CONCLUSIONS
  Exciting developments on ocular torsion have been described recently, and new ways to access and interpret ocular torsion have been devised as well.
authors.affiliation: Michigan State University, East Lansing, Michigan, USA.
authors.forename: João
authors.initials: J
authors.lastname: Lemos
authors.forename: Eric
authors.initials: E
authors.lastname: Eggenberger
mesh_terms: D005128:Eye Diseases / Q000175:diagnosis* / Q000628:therapy*; D006801:Humans; D012027:Reflex, Vestibulo-Ocular; D014102:Torsion Abnormality / Q000175:diagnosis* / Q000209:etiology / Q000628:therapy*; D020432:Trochlear Nerve Diseases / Q000150:complications / Q000175:diagnosis